An adaptive noise canceling technique was applied to word boundary
detection problems observed in a word recognition task under noise in a car.
Many word boundary detectors previously proposed only made use of sample
statistics of the short-term energy of incoming signal and noise, the operation
of which is often found unreliable and prone to errors with the existence of
radio talk and background music. In this study, an adaptive noise canceler was
employed that was based on a projection algorithm, and it was integrated into
the signal processing front end of a word recognizer as the pre-processing to
its word boundary detection, in order to reduce deletion errors and to improve
accuracy of detected boundary of the utterances by suppressing the effect of
co-channel components. Also observations were made of the behavior of the
integrated boundary detector in terms of the estimated profile of the short-term
energy, and its effect on the recognition accuracy were analyzed.